The invention relates to an arrangement for the further treatment of sectional steel, wherein the product issuing from the finishing roll train is coiled and is thereupon cooled in that form.
The invention is particularly applicable to rolled stock of relatively small cross-sectional area, i.e. stock that is easily coiled.
According to the present state of the art, small section rolling mills are equipped downstream of the finishing roll train with rotary shears for the purpose of cropping and dividing the lengths of rolled steel. The divided lengths are taken away on conveyor roll tables to one or two cooling beds. After the divided lengths have been conveyed across the cooling bed and cooled, they are passed in groups to single cold shears or pairs of cold shears having the appropriate feed devices for preliminary cutting. These pre-cut lengths are then straightened in straightening machines and cut again to their final size in shears having feed devices and are then passed to the relevant packaging and loading plants.
Such a plant with the above-described machinery for the further and final handling of the product requires very large and extensive factory bays and the expense thereof involves correspondingly heavy investment. There is considerable waste in cropping the ends of the rolled material and a relatively large proportion of sub-sized lengths so that the product includes a considerable proportion of scrap. Such plants are moreover labor intensive to an unusually high degree and labor costs are consequently very high.
The machines and apparatus mentioned above also have to contend with a plurality of technical problems, which adversely affect their operational reliability or else make much further development work necessary. Examples of such technical problems and requirements are:
1. The need to operate the cooling bed with optimum economy of material; PA1 2. Rotary shears suitable for a rolling speed of 20 m/sec with cropping action when needed; PA1 3. Cooling beds capable of dealing with rolled material fed in at a speed of 20 m/sec and over; PA1 4. Adequate levelling devices; PA1 5. Cold shears of adequate cutting capacity; PA1 6. Automatic devices for inserting cutter blades in the cold shears; PA1 7. Disposal of cropped ends and short lengths of rolled material; PA1 8. Singling and feed-in devices for the straightening machines, and PA1 9. Braking and collecting devices in the rear of the straightening machines. PA1 1. The space requirements for the plant can be reduced to 20 to 25% of the space required for hitherto customary plants, PA1 2. The capital investment costs for the plant amount to only about 68% of those for conventional plants, PA1 3. The productivity of the plant is increased, since only two croppings are required per rolled billet as compared with from two to 40 croppings hitherto, so that the cropping quota is considerably reduced, PA1 4. Fewer short length sections are produced and these can be more easily disposed of, PA1 5. It is easier to increase the rolling speed of the plant, PA1 6. The manning requirements of the plant are reduced, PA1 7. There is easier insertion of the rolled bars into the straightening machines and the sheering cutters, PA1 8. The finishing shops can operate independently of the actual rolling mills and PA1 9. The plant operating costs are considerably reduced. PA1 1. The cooling bed is dispensed with; the rolled stock (angle section, flat section and round section) is coiled and cooled in that form on conveyor belts or bands, PA1 2. The cooled section bar is unwound directly from the coils and straightened, PA1 3. Parallel section shears and a pre-positioned measuring roller parting the moving rolled bar are mounted in the rear of the straightening machine, the shears cropping the rolled bar and cutting it into separate (saleable) lengths, PA1 4. The separate lengths are taken off on slat conveyors circulating transversely to the straightening axis and are collected, and PA1 5. These lengths are discharged from the slat conveyors into a chute and can be packaged for dispatch.
There must be a satisfactory degree of coordination between all the machinery of the plant which must work in an operationally reliable manner, since breakdowns in individual units can lead immediately to severe losses of production.